A breath of fresh air: Why Grade L wins over Grade D air

Most people don’t consider the quality or grade of the air they are breathing. They don’t go to the grocery store and select Grade D air as they do their 1-percent milk. However, those in the petrochemical industry who use breathing air on worksites are very aware of the quality of the breathing air they purchase.

According to OSHA, any breathing air provided for use in the industry must comply with the standards of Grade D breathing air. OSHA defines Grade D air as suitable for breathing with the following characteristics:

Oxygen content of 19.5-23.5 percent

Hydrocarbon (condensed) content of 5 milligrams per cubic meter of air or less

Carbon monoxide content of 10 parts per million (ppm) or less

Carbon dioxide content of 1,000 ppm or less

Lack of noticeable odor

Dew point not to exceed -50 F.i

Although Grade D breathing air is the industry standard, Airgas On-Site Safety Services, the safety equipment rental division of Airgas Inc., believes Grade L air is a better solution. Because of its lower moisture content, Grade L reduces the risk of respiratory equipment malfunction and lost work time. Therefore, the group only provides Grade L product to its customers.

If using Grade D, it’s important to be aware of the complications that could occur due to the level of moisture found in this grade level. For example, when Grade D air is supplied through a respirator and face piece, the moisture in the air can interact with the rapidly expanding compressed air and cause a regulator to freeze up with the diaphragm stuck in an open or closed position, causing device malfunction. This is especially true in colder environments.

When malfunction occurs, the customer must take time-consuming and costly steps necessary to protect the safety of the user including inspection and repair of the equipment. If a malfunction occurs, the following steps are recommended:

1. Stop the work using the malfunctioned equipment.

2. Take the equipment to a qualified repair location to be inspected for any cracks or fractures created during the freeze.

3. Have the equipment properly serviced by authorized technicians. No one should reuse this equipment immediately after letting it warm and thaw.

Although a delay is the last thing a contractor wants during a scheduled maintenance project, failing to follow these steps could endanger the next person who uses the equipment.

System components can also be clogged or damaged by air with these acceptable moisture standards. This is because the moisture in breathing air can combine with other elements to form a contaminant. The Department of Transportation states, “Air contains moisture, which is drawn into the compressor and enters the air stream as a vapor. As compressed air flows through the system, it cools, causing the vapor to condense in the face piece or helmet. Moisture combines with oil and solid contaminants to form sludge, which can clog or damage system components.”ii

Due to these complications, many in the industry are turning to Grade L breathing air as it offers a reduced risk of complications in respiratory equipment. This, in turn, leads to a more productive work process with increased levels of safety.

SAFECOR has raised the standard for how Airgas purifies and compresses its breathing air products from the industry standard Grade D to Grade L and has mandated this standard when filling self-contained breathing apparatuses (SCBAs). Airgas On-Site Safety Services also applies the Grade L standard to all of the high-pressure breathing air it provides to customers even when compressing and purifying air on a customer’s jobsite. These efforts result in a product that is much drier than standard Grade D, drastically reducing the chance for moisture to create sludge or frozen equipment.

Especially when filling SCBAs, there is no backup air supply, so the highest quality air is required to mitigate risk. “SAFECOR has mandated everything we fill for SCBAs be of Grade L quality,” explained Shane Bates, national operations manager for Airgas On-Site Safety Services. “Therefore, at every Airgas On-Site Safety Services location, we’ve converted all purification and compressing processes to only provide Grade L. That means in every cylinder, in every cascade and in every trailer or jumbo tube, you receive Grade L breathing air, which helps reduce the risk for error. And to ensure we meet these standards every time in every location, we comply with and are audited on SAFECOR’s 60-step fill process and check list. Yes, it’s very redundant but redundancy develops trust.”

Selecting the right grade for your business

When it comes to the air employees breathe, there are choices. Although Grade D is the standard, more and more contractors are opting for Grade L breathing air for the health of their company’s equipment, employees and projects.

Whichever grade of breathing air is ultimately selected, Airgas On-Site Safety Services provides the product, equipment and services to complete work safely and efficiently.

For more information on Airgas On-Site Safety Services or SAFECOR, visit www.airgasonsitesafety.com or www.airgas.com, or call (877) 964-5463.